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// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information
// 
// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
// 
// http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// 

using System.IO;

namespace log4net.Util.PatternStringConverters
{
    /// <summary>Property pattern converter</summary>
    /// <remarks>
    /// <para>
    /// This pattern converter reads the thread and global properties.
    /// The thread properties take priority over global properties.
    /// See <see cref="ThreadContext.Properties"/> for details of the 
    /// thread properties. See <see cref="GlobalContext.Properties"/> for
    /// details of the global properties.
    /// </para>
    /// <para>
    /// If the <see cref="PatternConverter.Option"/> is specified then that will be used to
    /// lookup a single property. If no <see cref="PatternConverter.Option"/> is specified
    /// then all properties will be dumped as a list of key value pairs.
    /// </para>
    /// </remarks>
    /// <author>Nicko Cadell</author>
    internal sealed class PropertyPatternConverter : PatternConverter 
    {
        /// <summary>Write the property value to the output</summary>
        /// <param name="writer"><see cref="TextWriter" /> that will receive the formatted result.</param>
        /// <param name="state">null, state is not set</param>
        /// <remarks>
        /// <para>
        /// Writes out the value of a named property. The property name
        /// should be set in the <see cref="log4net.Util.PatternConverter.Option"/>
        /// property.
        /// </para>
        /// <para>
        /// If the <see cref="log4net.Util.PatternConverter.Option"/> is set to <c>null</c>
        /// then all the properties are written as key value pairs.
        /// </para>
        /// </remarks>
        protected override void Convert(TextWriter writer, object state) 
        {
            CompositeProperties compositeProperties = new CompositeProperties();

#if !NETCF
            PropertiesDictionary logicalThreadProperties = LogicalThreadContext.Properties.GetProperties(false);
            if (logicalThreadProperties != null)
            {
                compositeProperties.Add(logicalThreadProperties);
            }
#endif
            PropertiesDictionary threadProperties = ThreadContext.Properties.GetProperties(false);
            if (threadProperties != null)
            {
                compositeProperties.Add(threadProperties);
            }

            // TODO: Add Repository Properties
            compositeProperties.Add(GlobalContext.Properties.GetReadOnlyProperties());

            if (this.Option != null)
            {
                // Write the value for the specified key
                WriteObject(writer, null, compositeProperties[this.Option]);
            }
            else
            {
                // Write all the key value pairs
                WriteDictionary(writer, null, compositeProperties.Flatten());
            }
        }
    }
}
